2-Halo and 2,6-dihaloanilines are useful as intermediates in the manufacture of a wide variety of chemical products including, for example, dyes, pharmaceuticals and agricultural chemical. Unfortunately, 2-halo and 2,6-dihaloanilines, optionally substituted in the 3(5)- and/or 6-position, are often not that easy to obtain. Since direct electrophilic halogenation of anilines typically provides little or no selectivity for halogenation at carbons ortho versus para to the amino group, the 4-position must normally be blocked and then deprotected in order to prevent halogenation from occurring there. For example, 2,6-dichloro-3-methylaniline is presently manufactured from the acetanilide of m-toluidine in a multistep process (see O. G. Backeberg et al., J. Chem. Soc., 1943, 78-80; and H. C. Brimelow et al., J. Chem. Soc., 1951 1208-1212) involving the following reaction sequence: ##STR1## The yeilds of the protection (i) and chlorination (iii) steps are relatively low and the use of chlorosulfonic acid and ammonia present difficulties with respect to safe handling and waste disposal.
Rather than employing a scheme which involves the protection and deprotection of the reactive para position, it would be desirable to have a process in which a chloro or bromo substituent in the para position could be selectively removed from readily available anilines also having the same halogen in at least one of the ortho positions.